I. Field of the Invention
The present invention relates to piercing apparatus and more particularly to such an apparatus including a horizontally movable piercing means for piercing an arcuate workpiece.
II. Description of the Prior Art
Heretofore the removal of portions of arcuate workpieces has required a difficult and expensive machining operation. This has in the past taken the form of essentially hand machining each section to be removed. This, of course, is very expensive and, where a number of machining operations are required on each workpiece, results in substantial waste by reason of losses caused by improper machining of one portion when other portions have been completed.
Some efforts have in the past been made to machine such parts by electrical discharge machining (EDM) or electrical-chemical machining (ECM) but for a number of reasons these methods are not entirely satisfactory.
Because of these difficulties the fabrication of turbine or rotor wheels for instance has heretofore been accomplished by joining the blades to the arcuate rotor or turbine without the aid of locating apertures or slots. Since such blades must be precisely located and properly oriented, fixing them while welding or a similar joining operation is performed is very difficult.